Transdermal absorption preparation is generally produced by laminating an adhesive layer containing a drug on a substantially drug-impermeable support. Such transdermal absorption preparation is generally produced by applying a solution of an adhesive containing a drug in an organic solvent to the aforementioned support, drying the adhesive layer with hot air etc. to evaporate the organic solvent in the adhesive solution and, when desired, crosslinking the adhesive and the like.
When a drug is contained in an adhesive solution, however, since an undesirable phenomenon due to an interaction of the drug and the adhesive layer component may be developed, depending on the combination of the drug and the adhesive layer component, the decision of the formulation requires consideration that consumes time and expense. In addition, when an adhesive layer is subjected to a crosslinking treatment, since undesirable phenomenon such as crosslinking failure, denaturation of drug and the like due to an interaction of a certain kind of crosslinking agent and the drug can occur, the decision of the formulation requires consideration that consumes time and expense.
To remove such possibilities, a production method including applying an adhesive solution to a support and drying the same to give an adhesive sheet free of a drug (hereinafter sometimes to be referred to as “placebo”), applying, when desired, a crosslinking treatment, coating the surface of an adhesive layer with a drug liquid (i.e., liquid drug and/or drug solution), and allowing the drug to soak into the adhesive layer is advantageous.
JP-A-H11-502840 discloses a method for continuously manufacturing a pressure sensitive skin adhesive sheet material containing a liquid by combining a coating vehicle containing the liquid and a polymer base layer.
However, the production method disclosed in this publication does not disclose that a liquid component is contained in a pressure sensitive skin adhesive. Therefore, efficient impregnation of a pressure sensitive skin adhesive with a liquid pharmaceutical agent may be difficult. In addition, since this publication is directed to a coating vehicle containing a liquid rather than a pressure sensitive skin adhesive, this publication dissuades those of ordinary skill in the art to add a liquid component to an adhesive layer.
Moreover, this publication does not specifically disclose a method of impregnating a base layer with a pharmaceutical agent with regard to the manufacturing apparatus disclosed therein, let alone suggesting the time up to the impregnation of the adhesive layer with the coated drug solution, and an adhesive sheet traveling section for impregnation.
As mentioned above, the conventional techniques do not disclose or suggest an apparatus capable of producing a transdermal absorption preparation conveniently and efficiently, while avoiding disadvantages caused by the addition of a drug to an adhesive solution in the production of a transdermal absorption preparation.